Admixtures are substances that are added to concrete in order to enhance the quality of the concrete in some manner. Often, the role of admixtures is to expedite the curing process for the concrete, making it possible for the mixture to set and dry quickly. At other times, an admixture may be used to help slow down the setting and drying process, making it possible to work with the concrete for longer periods of time. Generally, admixtures are divided into two specific categories: mineral and chemical.
It is important to recognize that admixtures are different from aggregates. While it is true that aggregates also impact the final quality of the concrete, they are more concerned with texture and color. By contrast, admixtures are more focused on enhancing the workability of the concrete in some manner, as well as making it possible for the concrete to set and dry under various types of temperature conditions.
Most commercially produced concrete mixes sold today include at least one admixture as one of the main ingredients. In the United States, one of the most popular choices for admixtures is the inclusion of fly ash. Classified as a mineral admixture, fly ash helps to maintain the workability of the concrete, as well as increase the ability of the concrete to resist cracking over time due to expansion and contraction in different weather conditions. The ash is also great filler that makes it possible employ less concrete without negatively affecting the quality of the finished product.
Chemical admixtures are often added to concrete as a way to artificially control the rate or speed of curing. By having some degree of control over how long it will take the concrete to set once it is in place, it is possible to work with the concrete for longer periods of time in order to add decorative elements. At the same time, some chemical admixtures can accelerate the amount of time needed for the concrete to dry; this application is desirable when there is a need to create a basic structure or component with concrete and quickly move on to another task.
Overall, admixtures help to broaden the use of concrete for many different applications. Along with aggregates, admixtures can make a big difference in the look, feel and quality of the final product. By choosing the correct admixtures for the place and setting, it is possible to produce concrete products that hold up well and provide service for many years.
